In an ink jet head, ink is pressurized by a piezoelectric element and ink droplets are ejected through nozzles in a nozzle plate. An ink (or oil) repellent film applied on a surface of the nozzle plate prevents the ink from adhering to the nozzle plate. In an existing ink jet head, an oil repellent film is formed of a fluorine compound on the surface of the nozzle plate substrate, for example, by an application method or a vapor deposition method. The fluorine compound based film has a surface energy that acts to repel oils.